SAN JUAN, P.R., Oct. 5  An Election Day here, almost any Election Day, can cause dancing. "We enjoy voting," said 62-year-old Ana Esther Díaz from behind the counter of a sundries shop in San Juan.

"You can't drive in some places," said Ms. Díaz, because celebrations and last-minute campaigning choke the roads. Pork sizzles on the grill.

And at night there is music, she said, "music and noise," on an island where voter turnout is, traditionally, more than 80 percent.

But when it comes to electing an American president, the people in this United States commonwealth have been barred, under the United States Constitution, from the biggest party of all. They are allowed to vote in presidential primaries, but, historically, not in the general election.

"We are American citizens," Ms. Díaz said. "We should get to vote."

With the presidential election just a month away, many people here are hoping that a federal appeals court in Boston will uphold a federal judge's ruling that allows them to vote in the presidential election for the first time.

The ruling has become one of the hottest issues in the campaign for governor, and has fueled the debate over the political status of Puerto Rico.

This week, the United States Court of Appeals for the First Circuit, in Boston, heard arguments on whether the island's 2.4 million registered voters may vote for president on Nov. 7.

Speaking before a panel of three judges at the federal appeals court in Boston, a team of Puerto Rican officials said the right of a United States citizen to vote was more fundamental than the Electoral College system.

"You're pretty much undermining, striking at the heart of democratic government," said Angel E. Rotger Sagat, attorney general of Puerto Rico.

And Gregorio Igartua de la Rosa, a lawyer representing 11 Puerto Ricans who brought the lawsuit in federal court, called the Department of Justice's effort to have the case dismissed a "discriminatory appeal."

The lawyer for the United States, Matthew Collette, reiterated that there were two ways for Puerto Rico to gain the vote. "One is statehood, the other is a constitutional amendment such as the 23rd," he said.

But Gov. Pedro Rosselló of Puerto Rico, who attended the hearing, stood by his determination to include a presidential ballot in the commonwealth's elections on Nov. 7.

"We intend to go forward with what is now law in Puerto Rico," said Mr. Rosselló, who has pushed for statehood for Puerto Rico as leader of the New Progressive Party. Justice Department officials in Washington, as well as political experts on and off the island, say they believe the appeals court will overturn the ruling by the federal district judge in San Juan, and quiet the celebration before it even begins.

Puerto Ricans, American citizens since a vote by Congress in 1917, are not allowed to vote for president when they live on the island because Puerto Rico is not a state.

But Judge Jaime Pieras of Federal District Court in San Juan, responding to the most recent of several lawsuits that have challenged the law, ruled on Aug. 29 that Puerto Ricans, as United States citizens, had the right to vote in a general election.

Judge Pieras pointed out that while all United States citizens who live outside the United States were allowed to vote in absentia for president, Puerto Ricans who could vote in a general election while living in one of the 50 states lost that right when they returned to the island.

He ordered that the island's government act "with all possible expediency" to make it possible for citizens here to vote in the election.

Governor Rosselló moved quickly to sign a law permitting such a vote even when the political opposition voiced skepticism that the vote would be allowed to stand.

Justice Department officials appealed the Federal District Court decision and said the Constitution clearly refuted the judge's ruling. The department has asked the Court of Appeals for a speedy resolution, because of how its ruling could affect the presidential election.

For Puerto Ricans, many smarting from the United States Navy's use of the island of Vieques for bombing practice, the Justice Department's fight to quell their vote is a personal affront.

"The United States wants us for some things, like Vieques, but for other things they set us apart," said Stephen Rivera, who runs a surf shop in San Juan. "If we are U.S. citizens, why can't we vote?"

The case is one more facet of a continuing debate over Puerto Rico's political status, whether to seek statehood and pay federal taxes, which islanders do not now pay, or leave things the way they are.

Leaving the commonwealth status as it is has been the way most Puerto Ricans want it, according to the results of recent referendums. But pro- statehood sentiment is gaining steadily, and independence has only a small minority of advocates. The commonwealth status, while leaving island residents free of federal taxes, subjects them to the United States military draft.

And that is an argument many people here make for gaining the right to vote for a president with or without statehood. Puerto Ricans have fought in every war since World War I, yet have no voice in choosing a commander in chief.

"They die for the United States," Ms. Díaz said. "Sometimes they don't even know what they're dying for, but they die." It is not unreasonable, people here say, to trade such sacrifice for the right to vote for a president.

But Silvia Álvarez-Curbelo, director of the Communications Research Center at the University of Puerto Rico's School of Public Communications, said the debate over the vote for president obscures the real issue: statehood.

"I think it's all wishful thinking," Ms. Álvarez-Curbelo said of the legal fight. "It's very clear constitutionally, Puerto Ricans can't vote. We either need an amendment to the Constitution or Puerto Rico needs to become a state."